Xenon arc infrared power system



Oct. 18, 1966 Filed Jan. 20, 1964 M. C. BAUM ETAL 2 SheetsSheet 1 F I QR??? I l3 1 I 14 II I I 1 XENON v 11c. fly ARC I7 I l2 l l r ls" a 20 KC o wag; POWER :24 vac. V OSCILLATOR vvu l 24 l l l 25 /29 l/--- STARTER 25 i XENON i 1 I 27 I ARC INVENTORS MATTHEW C. BAUM JOSEPH LaRUSSA w ways,

Oct. 18, 1966 M. c. BAUM ETAL 3,280,369

XENON ARC INFRARED POWER SYSTEM Filed Jan. 20, 1964 2 Sheets-Sheet 2 TRABCIJSIEEOR 3 4 o P W 2 VDC OSCILLATOR uovuc.

TRANSISTOR w usv 400% as 1 L 1 I 35 as l w ==J37 i l THERMAL 5| l DELAY 1, SWITCH I 59 44 *4 54 55 I I I 65-1 S "I l :v l I 4| nsv 'LZ-B "4OQ3 42-L-== l s3 s4 L I HIGH v62 VOLTAGE 61 STARTER Y 56 48 INVENTORS MATTHEW C. BAUM JOSEPH LaRUSSA TYS.

United States Patent 3,280,369 XENON ARC INFRARED POWER SYSTEM Matthew C. Baum, New York, and Joseph La Russa,

Yonkers, N.Y., assignors, by mesne assignments, to the United States of America as represented by the Secretary of the Navy Filed Jan. 20, 1964, Ser. No. 339,041 5 Claims. '(Cl. 315-243) The present invention relates generally to radiant energy generating systems and in particular is a starter and power supply system for energizing a xenon arc infrared lamp.

In order to obtain stable operation of xenon arc lamps, it is necessary to regulate the current through the lamp, rather than the voltage across it. This is due to the fact that at low currents the lamp exhibits a negative resistance while for currents in the normal operating range they have a dynamic resistance close to zero.

In the arc lamp power supplies of the prior art, several methods of current control have been employed which are satisfactory for some purposes. For alternating current power supplies, a reactive ballast is placed in series with the xenon lamp, while for direct current power supplies, a resistive ballast is used. For some applications, the direct current operation is most feasible, since the lamp is actually capable of following an alternating current but the resulting envelope modulation is sometimes objectionable. Unfortunately, most of the commercially available prior art ballasts are particularly undesirable because of their size, weight, and, especially, because of their inefficiency. For example, in a typical commercial unit used to regulate a 900 watt xenon arc, the resistive ballast measured 26 by 16 inches and weighed 27 pounds. Furthermore, it dissipated 2400 watts of power-a considerable amount, considering the 900 watts of useful output obtained therefrom. In addition, because the xenon arc lamp required approximately 30,000 volts in the radio frequency range to break down the are, a typical commercially available unit that will produce such voltage weighs approximately 16 pounds, occupies a relatively large volume, and requires about 20 to 30 seconds to start the arc.

The instant invention overcomes most of the foregoing disadvantages because it is comparatively small in size, light in weight, and highly eflicient as a result of uniquely interconnected and interacting solid-state elements being employed therein.

For the purpose of making an exemplary comparison between the subject invention and the prior art devices the following table lists the relative operational values thereof:

Operational Parameter Subject Invention Prior art Devices Power Input 1,200 Watts 3,300 watts. Power Output 900 Watts. Efilciency 27.3% Starting time... 20-30 sec Power supply wt 27 lbs. Starter wt 16 lbs. Total wt 9lbs., 9 oz 43 lbs.

sult of using the teachings and concepts of this invention probably falling into a superior category for most practical purposes.

It is, therefore, an object of this invention to provide an improved xenon are power supply.

Another object of this invention is to provide an improved method and means for starting an xenon arc lamp.

Still another object of this invention is to provide a more efiicient method and means for starting and powering an xenon arc lamp.

A further object of this invention is to provide an xenon arc powering system that is relatively small in size and light in weight.

A further object of this invention is to provide a method and means of producing a flashing xenon arc containing infrared radiant energy as well as visible radiant energy that may be expediently used in buoys or other mounting devices to facilitate navigation of boats, ships, aircraft, landcraft, or any other appropriate vehicles.

Another object of this invention is to provide a more reliable method and means for starting and powering a xenon arc.

Still another object of this invention is to provide a xenon arc starting and powering system that is easily and economically manufactured, maintained, and operated.

Other objects and many of the attendant advantages will be readily appreciated as the subject invention becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying figures of the drawing wherein:

FIG. 1 is a schematic diagram of the basic circuit of the subject invention;

FIG. 2 is a combined schematic and block diagram of a more sophisticated version of the basic form of the subject invention; and

FIG. 3 is a detailed schematic and block representation of the subject invention.

Referring now to FIG. 1, there is shown a direct current voltage input at a pair of terminals 11 and 12. Connected in series with said terminals 11 and 12 are a reactive ballast and current regulating inductance 13, a Xenon arc lamp 14, and a switch 15. Connected in parallel with xenon arc lamp 14 is a capacitor 16, and connected between terminal 11 and the junction of lamp 14 and switch 15 is a diode 17. The aforementioned inductance'13-capacitor 16 combination, of course, constitutes a reactive low pass filter 18, and the entire basic circuit acts as a direct current transformer circuit.

The embodiment of FIG. 2 depicts a twenty kilocycle per second power oscillator 21, preferably of the transistorized circuitry type, which has the input thereto connected to a 24 volt direct current supply and the output thereof coupled to a power switch 22, likewise preferably of the transistorized circuitry type. A volt direct current supply is also coupled to power switch 22. Of course, the aforesaid oscillator and switch are well known and conventional, per se, so it is deemed unnecessary to further define the detailed circuitry thereof at this time.

The output of power switch 22 is coupled through a diode 23 to ground, and a series connected current regulating ballast inductance 24 and xenon arc lamp 25 is connected in parallel with the aforementioned diode 23. Also, a series connected switch 26 and capacitor 27 are parallel connected with the aforesaid xenon arc lamp 25, and when switch 26 is closed, the combination thereof with inductance 24 and capacitor 27 form a low-pass filter 28. A starter 29 is transformer coupled to one of the electrical leads to xenon arc lamp 25 by means of a winding 30 which timely supplies suflicient current to break down the Xenon arc. Starter 29 and switch 26 are so connected that closure of switch 26 actuates starter 29 to simultaneously produce said break down current.

The other preferred, detailed embodiment of the subject invention is illustrated in FIG. 3 as having a transistor power oscillator 31 coupled to the input of a transistor high power switch 32. Oscillator 31 and switch 32 have respectively applied thereto a 24 volt direct current supply and a 110 volt direct current supply. Connected across transistor high power switch 32 is a diode 33. Another diode 34 is connected between the 110 volt D.C. input of switch 32 and a relay switch 35, with switch 35 also being connected through another diode 36 to a 115 volt, 400 cycle supply and through a capacitor 37 to ground. Diode 34 is also connected through an inductance 38, a relay solenoid 39, another relay switch 41, and a capacitor 42 to ground. The output of transistor high power switch 32 is coupled through a diode 43 to ground and through an inductance 44 to the non-grounded side of said capacitor 42.

A pair of series connected resistors 45 and 46 are connected to one of the electrodes 47 of a xenon arc lamp 48, with the other electrode of lamp 48 being connected to ground. Connected in parallel with resistor 46 is a capacitor 49 and the emitter and collector elements of a PNP transistor 51, with the collector thereof also coupled to electrode 47 of xenon are 48. The base of said transistor 51 is coupled through a capacitor 52 to the junction of resistor 46 and electrode 47 and to the movable arm of a relay switch 53. Switch 53 is a single throw-double pole switch with the stationary contacts thereof respectively connected to the aforesaid emitter and collector elements of transistor 51. The electrical junction of solenoid 39 and switch 41 is coupled to electrode 47 of xenon arc lamp 48.

A capacitor 54 is connected between the 110 volt D.C. input of transistor high power switch 32 and ground, and another capacitor 55 is connected between electrode 47 and ground. The other electrode 56 of xenon arc lamp 48 is likewise connected to ground to complete the circuit thereto.

A thermal delay switch 57, of the type which closes as a result of being exposed to some given temperature for a predetermined time period, is connected through a relay solenoid 58 and a switch 59 to the aforesaid 110 volt D.C. input to switch 32. To complete the circuit, thermal delay switch 57 is also connected to ground. Of course, as shown, solenoid 58 and switch 41 are both parts of a relay with the former adapted for timely opening and closing the latter.

A conventional high voltage starter 61 is transformer coupled by a winding 62 to the electrical lead connected to electrode 47 of xenon arc lamp 48 for timely supplying a predetermined high RF voltage thereto. To effect this, said starter 61 is connected between ground and a start switch 63, which is ordinarily closed manually by a human operator to start the device constituting this invention operating in its normal manner. Another switch 64 interconnects switch 63 and a 115 volt, 400 cycle power supply.

At this time, it should be noted that the aforesaid switches 35, 53, and 64 are the switch portions of a relay. They are ganged together for simultaneous operation thereof by the aforesaid solenoid 39, and in this particular case, they are normally closed as shown in FIG. 3 and are actuated to the respective opposite conditions only when solenoid 39 is in an energized condition.

Briefly, the operation of the various preferred embodiments of the subject invention is as follows:

Considering first the most basic circuit shown in FIG. 1, it can readily be Seen that when switch 15 is closed, the current flows across xenon are 14 and through inductance 13 while charging capacitor 16. Then, opening switch 15 turns off the supply current and the magnetic field originally created by inductance 13 in a direction opposing the original current flow begins to collapse. As .said field collapses, it induces a voltage in inductance 13 in the diIt CI OIL that will continue to maintain the original current flow through the coil thereof. Thus, the reversed voltage polarity across inductance 13 presents the same electrical condition to xenon are 14 as when it drew its current directly from the direct current voltage supply.

As a result of such current How and the polarity thereof, diode 17 conducts to complete the circuit, keeping the xenon are going until such time as the energy stored in the form of a magnetic field in inductance 13 is dissipated sufiiciently to decrease the current flow to the extent that the xenon arc will be cut off. Of course, closing switch 15 again at the proper time will prevent such cutoff, since xenon arc lamp 14 effectively experiences a substantially constant supply of regulated direct current which is smoothed by capacitor 16. Should it be desired that xenon arc lamp operate intermittently, the closing and opening of switch 15 at the proper frequency will cause this condition to be effected.

In the device of FIG. 2, power switch 22 performs the same switching operation as manually operated switch 15 did in the more basic device shown in FIG. 1. Moreover, the oscillator 21 causes switch 22 to be switched at an optimum rate. Because the power dissipated by a switching transistor occurs primarily due to the power expended in accomplishing the transition from a fully off condition to a fully on conducting state, it should be obvious that the transition time therebetween must be as short as possible in order to obtain optimum efiiciency. Therefore, it is necessary for the oscillator driving said power switch to have a rise time that in short as possible. In this case, a 20 kilocycle per secod oscillator with a rise time of the order of 0.5 microsecond was selected because it is unusually stable in its operation and produces a relatively clean wave form over a wide range of load. Hence, the oscilator-power switch arrangement allows the power switch to transfer thirty amperes of current from a volt D.C. power source in approximately twenty-five microseconds with rise and fall times of the order of threetenths microseconds. A starter switch 26 and an RF high voltage booster starter circuit 29 have been added in addition to the aforesaid oscillator and power switch in order to refine the overall operation and make it more automatic as a result of improved current regulation. Otherwise, the device of FIG. 2 functions in the same way as the device of FIG. 1 to force regulated D.C. current through xenon arc lamp 25. Again, it should be noted that capacitor 27 (like the aforementioned capacitor 16) smooths the current flow and substantially removes switching frequency components therefrom.

It is apparently noteworthy that if switch 26 is a good switch and diode 23 likewise acts like a good switch and if inductance 24 and capacitance 27 are high-Q components, then all the electrical energy entering from the line must flow through the arc. Since, in this embodiment, the xenon arc maintains a substantially constant voltage drop of approximately 32 volts across its electrodes while the line potential is 110 volts, the current in the line should be approximately A of the current that flows in the are. This gives the circuit the property of acting as a D.C. Transformer. That this type of D.C. operation, with an equivalent reactive ballast for current regulation, results in unusually high power efficiency in the subject system, has been verified by experimentation.

The operation of the embodiment of FIG. 3 is generally similar to that of the devices of FIGS. 1 and 2. However, some detailed refinements have been incorporated therein which improve the operation thereof.

Not only do new xenon arc lamps exhibit variations in breakdown potential but these characteristic change for any given lamp due to electrode wear, lamp aging, and the like; consequently, it is often diflicult to strike an arc with just a standard starter. Hence, the combination of elements in the device of FIG. 3 has been found to be very satisfactory, in that they facilitate automatic lamp starting with ususual reliability. The specific sequence of operation thereof is as follows:

With the contacts of switches 35, 53, and 64 in their normally closed position as shown, transistor 51 is forward biased and acts as a diode, shorting resistor 46. Capacitor 37 is charged to the peak line voltage of the 400 cycle input by means of diode 36 to provide a potential of approximately 170 volts at the anode electrode of the xenon arc, and when starter button switch 63 is closed, RF high voltage starter 61 creates an ionized path across the xenon lamp electrodes and approximately 50 ampers fiow through the lamp. Choke 38 delays the pull-in current through relay solenoid 39 for some milliseconds, and this delay is sufficient to insure establishment of the xenon lamp arc. After said delay occurs, solenoid 39 becomes fully energized and opens switches 35 and 64 and positions switch 53 in its other closed position, thereby disconnecting capacitor 37, disconnecting the power to RF high voltage starter 61, and applying a reverse bias to transistor 51, respectively. This reverse bias then causes transistor 51 to limit the current through lamp 48 to approximately four amperes. After several minutes have elapsed and xenon arc lamp 48 is warm from running on four amperes, thermal delay switch 57 (or any other delay type switch operated by any preferred appropriate parameter) closes, causing switch 41 to be closed and the balance of the current required for rated power operation to be supplied to lamp 48. Of course, once switch 41 is closed, inductance 44 and capacitance 42 constitute a low pass filter 65. Switch 35 is opened to prevent the charge on capacitor 37 from reaching the transistor power switch 32, while diodes 33 and 34 limit the voltage for the protection of said power switch.

Once the arc is running normally within lamp 48, both infrared and visible radiant energy are generated thereby which may advantageously be used for many purposes, including those mentioned above.

Obviously, many modifications and other embodiments of the subject invention will readily come to the mind of one skilled in the art having the benefit of the teachings presented in the foregoing description in accompaniment with the associated drawing. Therefore, it is to be understood that the invention is not to be limited thereto and that said modification and embodiments are intended to be included within the scope of the appended claims.

What is claimed is:

1. Means for starting and powering an electric arc within a gaseous medium comprising in combination:

a gaseous medium capable of being ionized;

a pair of electrodes disposed within said gaseous medium;

a capacitor connected across said pair of electrodes;

an inductor connected to one of said pair of electrodes;

a diode connected in series with said inductor, with said series connected inductor and diode connected in parallel with the aforesaid capacitor;

a pair of electrical terminals adapted for receiving a direct current voltage, with one terminal thereof coupled to the junction of said diode and said inductor; and

a switch means interconnecting the other terminal of said pair of electrical terminals and the other electrode of said pair of electrodes.

2. A xenon arc infrared lamp starting and power system comprising in combination,

an oscillator,

a power switch coupled to the outputof said oscillator,

a ground,

a diode having a cathode and an anode with the cathode thereof connected to the output of said power switch and the anode thereof connected to said ground,

an inductance having a pair of electrical terminals with one of the terminals thereof coupled to the output of said power switch,

a Xenon arc lamp connected between the other electrical terminal of said inductance and said ground,

a switch having a movable contact and a stationary contact with the movable contact thereof connected to the junction of said inductance and xenon arc lamp, and

a capacitor connected between the stationary contact of said switch and said ground.

3. The invention according to claim 2 further characterized by a starter means connected for activation by said switch and for timely supplying radio frequency energy to said Xenon arc lamp when said switch is closed.

4. A Xenon are starting and powering system comprising in combination:

a xenon arc lamp;

means effectively connected to said xenon arc lamp for initially striking an electric arc thereacross;

means connected to said initial are striking means and said Xenon arc lamp for limiting the current therethrough for a predetermined warm-up period after said are has been struck, said current limiting means including a resistor connected in series with said xenon arc lamp, a capacitor connected in parallel with said resistor, a transistor connected in parallel with said resistor with said transistor being timely biased to be non-conductive and timely biased to be conductive for shorting out said resistor, and means for biasing said transistor to be non-conductive during the aforesaid warm-up period and conductive during the period said xenon arc lamp is operating at rated power; and

means connected to said are striking and current limiting means for supplying a substantially regulated current at rated operational power to said xenon arc lamp at the termination of the aforesaid warm-up period.

5. The invention according to claim 4 further characterized by means connected to said transistor biasing means for effecting a predetermined delay period between the biasing of said transistor in a non-conductive state and a conductive state.

References Cited by the Examiner UNITED STATES PATENTS 2,916,671 12/1959 Retzer 315176 2,944,191 7/1960 Kapteyn 315-241 2,993,144 7/1961 Grabner et a1. 315183 3,004,191 10/1961 Umbarger 315-241 3,011,094 11/1961 Kapteyn 315183 3, 017,538 1/1962 Sakaki 315-241 3,066,243 11/ 1962 Mutschler 315241 X 3,163,755 12/1964 Kotz et al 315241 X 3,165,668 1/1965 Harpley 315290 X JOHN W. HUCKERT, Primary Examiner. MAYNARD WILBUR, Examiner. I. D. CRAIG, Assistant Examiner. 

1. MEANS FOR STARTING AND POWERING AN ELECTRIC ARC WITHIN A GASEOUS MEDIUM COMPRISING IN COMBINATION: A GASEOUS MEDIUM CAPABLE OF BEING IONIZED; A PAIR OF ELECTRODES DISPOSED WITHIN SAID GASEOUS MEDIUM; A CAPACITOR CONNECTED ACROSS SAID PAIR OF ELECTRODES; AN INDUCTOR CONNECTED TO ONE OF SAID PAIR OF ELECTRODES A DIODE CONNECTED IN SERIES WITH SAID INDUCTOR, WITH SAID SERIES CONNECTED INDUCTOR AND DIODE CONNECTED IN PARALLEL WITH THE AFORESAID CAPACITOR; A PAIR OF ELECTRICAL TERMINALS ADAPTED FOR RECEIVING A DIRECT CURRENT VOLTAGE, WITH ONE TERMINAL THEREOF COUPLED TO THE JUNCTION OF SAID DIODE AND SAID INDUCTOR; AND A SWITCH MEANS INTERCONNECTING THE OTHER TERMINAL OF SAID PAIR OF ELECTRICAL TERMINALS AND THE OTHER ELECTRODE OF SAID PAIR OF ELECTRODES. 